dvd bitrate how much is enough?

[houseng]

i normally convert my video to one hour dvd (mp3g-2) file...which is at about 8000kbps average bitrate to fit to a 4.7GB dvd. but now that i have a 2 hour video which i want to fit in a 4.7GB dvd... so i want to ask how much bitrate is good enough that u can't see a difference between the quality of the original video and the mp3g-2 file.

[bugster]

There is no correct answer to this question.

The amount of bitrate required is affected by many factors including, but not limited to, the quality of the source, the amount of movement (including camera shake from hand hel cameras, a BIG consumer of bitrate!), lighting conditions and changes etc.

Encode with whatever average bitrate you need to fit the movie on one DVDr, but use 2-pass VBR encoding for the best chance of good quality.

[andkiich]

There is a lot of subjectivity here, and a lot of depends:

How noisy is the source? This will eat a lot of bitrate if it is noisy.
What encoder are you using?

The best thing to do would be to encode a small section of the DVD(about 15 minutes worth) at the maximum bitrate that will fit 2 hours on a DVDR. Use the bitrate calculator on this site(TOOLS) to determine the bitrate.

If it meets your expectations, you're good to go, if not, you might need to stick with only 1 hour per disc. That, ultimately, will be your call as quality of any finished product is subjective.

[pyrohydra]

Two hours of full resolution footage will require an (average) bitrate of around 4800kbps. This in my opinion will definitely be pushing mpeg2 compression to its limit, and you may notice artifacts during high motion scenes, or scenes in which the camera shakes a lot.

If I were you I would simply split that footage across 2 discs and just encode at 8000 kbps CBR. If this doesn't suit you, you could also resize to 352x480 (I'm assuming this is NTSC footage), but this will also cause a substantial loss in quality.

[daamon]

If this doesn't suit you, you could also resize to 352x480 (I'm assuming this is NTSC footage), but this will also cause a substantial loss in quality.

Two things here:

1. The lower resolution of 352x480 (known as 1/2 D1) is not limited to NTSC. You can do 1/2 D1 PAL - it's just that it's 352x576 not 480.

2. I'd disagree with the words "substantial loss in quality" - the effect of encoding to 1/2 D1 is to lose some sharpness - not really a problem if the source is VHS (320 x 240). If it's not, it's still not a huge effect unless you're watching on a high-definition wide-screen TV.

The simple thing is to check out an encoding for a short clip at 1/2 D1 with 2-pass VBR (min = 1,000 kbps, average = around 3,000 kbps and max = around 5,000kbps). See if you like it...

Hope that helps...

[gratner]

In my experience with transferring VHS to DVD 5000kbps has worked suitably and I can fit around 2 hrs on a DVD with no problems.

Since my source is bootleg video, some of it old and a bit noisy and I've not found it to be a problem.

[daamon]

Hi gratner,

As your source is a bit noisy, you may want to look into various filters for noise reduction / tidying it up etc. From memory, I think SatStorm has posted recently on this - it might be worth trying to do a search...

As for "bootleg" videos - you're on shaky ground there (read the forum rules at the top of the page when posting). Best not mentioning things like that in the forums...